Screening and Prognostic Value of Methylated Septin9 and its Association With Clinicopathological and Molecular Characteristics in Colorectal Cancer

Dynamic Changes in Circulating Methylated Markers in Response to Antitumor Therapy of Rectal Cancer

BACKGROUND

Rectal cancer (RC) occupies a leading position in the structure of oncological morbidity and mortality. Aberrant methylation of tumor-suppressor genes and hypomethylation of retrotransposons were shown to be detectable in cell-free DNA, circulating in the blood (cfDNA) of cancer patients, indicating the possibility to use them as diagnostic and prognosis markers.

PURPOSE

Evaluation of the changes in the methylation level of LINE-1 elements and SEPTIN9 and IKZF1 genes in the cell-surface-bound cfDNA (csb-cfDNA) from the blood of RC patients after antitumor therapy at a long-term follow-up.

METHODS

Blood samples were obtained from RC patients (n = 25) before treatment, after preoperative chemotherapy (3 courses according to the XELOX scheme), 10-15 days after surgery, and every 3 months during 12 months of dynamic observation. The methylation level of LINE-1, SEPTIN9, and IKZF1 in the csb-cfDNA was evaluated by quantitative methyl-specific PCR.

RESULTS

The LINE-1 methylation level in the csb-cfDNA increased 1.6 times in RC patients after chemotherapy and 3 times after tumor resection versus methylation level before therapy. The SEPTIN9 gene methylation level in the csb-cfDNA decreased by 1.7 times in RC patients after chemotherapy and by 2.3 times after tumor resection compared with the values before the treatment. The IKZF1 gene methylation level decreased by 2 times in RC patients after combined therapy. Notably, all patients with relapses (n = 5) showed an increase in methylation level for the SEPTIN9 and IKZF1 genes and a decrease of methylation level for the LINE-1 elements by 2 times or more in comparison with the level 10-15 days after surgery. There were no changes in the circulating SEPTIN9, IKZF1, and LINE-1 methylation levels during the 12-month follow-up period after the combined therapy of RC patients (n = 20) without relapses.

CONCLUSION

The results indicate that SEPTIN9, IKZF1, and LINE-1 methylation levels in the csb-cfDNA are potential markers of the effectiveness of antitumor therapy and early detection of relapse in RC patients.

Blood-based colorectal cancer screening in an integrated health system: a randomised trial of patient adherence

OBJECTIVE

We evaluated whether people who had not completed a faecal immunochemical test (FIT) for colorectal cancer (CRC) screening would complete a blood-based testing option if offered one during health encounters. Blood-based screening tests for CRC could add to the total number of people screened for CRC by providing another testing alternative.

DESIGN

Study participants were patients aged 45-75 years at a large, integrated health system who were offered but did not complete an FIT in the prior 3-9 months and were scheduled for a clinical encounter. Individuals were randomised (1:1) to be offered a commercially available CRC blood test (Shield, Guardant Health) versus usual care. We compared 3-month CRC screening proportions in the two groups.

RESULTS

We randomised 2026 patients; 2004 remained eligible following postrandomisation exclusions (1003 to usual care and 1001 to blood draw offer; mean age: 60, 62% female, 80% non-Hispanic white). Of the 1001 allocated to the blood test group, 924 were recruited following chart-review exclusions; 548 (59.3%) were reached via phone, of which 280 (51.1%) scheduled an appointment with the research team. CRC screening proportions were 17.5 percentage points higher in the blood test group versus usual care (30.5% vs 13.0%; OR 2.94, 95% CI 2.34 to 3.70; p<0.001).

CONCLUSION

Among adults who had declined prior CRC screening, the offer of a blood-based screening test boosted CRC screening by 17.5 percentage points over usual care. Further research is needed on how to balance the favourable adherence with lower advanced adenoma detection compared with other available tests.

TRIAL REGISTRATION NUMBER

NCT05987709.

Detection of methylated BCAT1 and IKZF1 after curative-intent treatment as a prognostic indicator for colorectal cancer recurrence

BACKGROUND

The risk of recurrence after completion of curative-intent treatment of colorectal cancer (CRC) is hard to predict. Post-treatment assaying for circulating tumor DNA (ctDNA) is an encouraging approach for stratifying patients for therapy, but the prognostic value of this approach is less explored. This study aimed to determine if detection of methylated BCAT1 and IKZF1 following completion of initial treatment identified patients with a poorer recurrence-free survival (RFS).

METHODS

142 CRC stage I-III cases with at least 2 years of follow up (unless recurrence was evident sooner) and a methylated BCAT1/IKZF1 test result between 2 weeks and 12 months after completion of initial treatment were eligible for study inclusion. The association between BCAT1/IKZF1 and RFS was assessed by the log-rank (Mantel-Cox) method. Cox proportional hazard regression analysis was used for multivariable survival analysis.

RESULTS

Thirty-three (23.2%) had recurrence at a median 1.6y (interquartile range: 0.8-2.4). Methylated BCAT1/IKZF1 was detected in 19 of the 142 patients (13.4%) and was associated with a significant risk of recurrence (hazard ratio [HR] 5.7, 95%CI: 1.9-17.3, p = 0.002). Three-year RFS for patients with or without detectable methylated BCAT1/IKZF1 was 56.5% and 83.3%, respectively. Multivariable analysis showed that detection of methylated BCAT1/IKZF1 (HR = 2.6, p = 0.049) and site of the primary tumor (HR = 4.2, p = 0.002) were the only significant prognostic indicators of poor RFS.

CONCLUSIONS

BCAT1/IKZF1 methylation testing after curative-intent treatment is an independent prognostic indicator for RFS and identifies a subgroup at high risk. Personalized surveillance is warranted for patients with these ctDNA biomarkers detectable after curative-intent treatment.

Methylated Septin 9 as a Promising Biomarker in the Diagnosis and Recurrence Monitoring of Colorectal Cancer

Purpose. The clinical utility of plasma methylated septin 9 (mSEPT9) DNA in screening and recurrence monitoring for colorectal cancer (CRC) is highly promising. The present study was performed to determine the diagnostic value of mSEPT9 in CRC detection and recurrence monitoring in Chinese patients. Methods. Overall, 616 patients newly diagnosed with CRC and 122 individuals with no evidence of disease were recruited from October 1, 2019, to May 31, 2021, at Fujian Medical University Union Hospital. Plasma and serum samples were collected for analyzing mSEPT9, carcinoembryonic antigen (CEA), and carbohydrate antigen-19-9 (CA19-9). Data on clinicopathological characteristics were collected and analyzed. Sensitivity and specificity were calculated to evaluate the diagnostic potential of each marker; the receiver operating characteristic (ROC) curve was applied for the assessment of diagnostic value, and comparisons among mSEPT9, CEA, CA19-9, and their combination were assessed via ROC curves. Results. mSEPT9 achieved an overall sensitivity and specificity of 72.94% and 81.97%, respectively, with an area under the curve (AUC) value of 0.826, which were higher than those of CEA (sensitivity: 43.96%; specificity: 96.72%; AUC: 0.789) and CA19-9 (sensitivity: 14.99%; specificity: 96.61%; AUC: 0.590). The combination of mSEPT9, CEA, and CA19-9 further improved sensitivity, specificity, and AUC value (sensitivity: 78.43%; specificity: 86.07%; AUC: 0.878), respectively. Notably, the mSEPT9 positivity rate was significantly associated with TNM stage, T stage, N stage, tumor size, vascular invasion, and nerve invasion among patients with CRC. A 100% correlation was observed between the positive results of the mSEPT9 test and recurrence or metastasis in patients after therapeutic intervention. Conclusion. Our findings suggest that mSEPT9 may represent a potential biomarker for the diagnosis and prognosis of CRC compared with CEA and CA19-9. Postoperative mSEPT9 status may represent the first noninvasive marker of CRC recurrence or metastasis.

Methylated septin 9 gene is an important prognostic marker in stage II and stage III colorectal cancer for evaluating local recurrence or distant metastasis after surgery

BACKGROUND

Abnormal hypermethylation of the septin 9 gene was an inchoate incident in some cancers. Though latest several researches had paid attention to its value in prognosis, the consequences were not distinctly, especially in colorectal cancer (CRC) with stage II and stage III.

PURPOSE

The aim of this research was to pick up the prognostic value of the methylated septin 9 gene (mSEPT9) in CRC patients, particularly in TNM stage II-III.

METHODS

Blood samples before surgery were obtained from 144 CRC patients, of which there were 94 with stage II and stage III. mSEPT9 was considered positive when the cycle number of the peak reaction (Ct) was lower than the threshold value (41.0) for two times during three times PCR test. mSEPT9 and other relative factors of prognosis were estimated by survival analysis. The level of septin 9 in tissues was tested by immunohistochemical (IHC).

RESULTS

Stage II and stage III patients with mSEPT9 positive (mSEPT9+) had a lower disease-free survival (DFS) rate than those with mSEPT9 negative (mSEPT9-) (2-year DFS rates, 52.1% vs 73.9%, P = 0.014). In multivariate regression analysis, mSEPT9 was also an independent predictor of prognosis (HR = 2.741, P = 0.009). The risk of local recurrence or distant metastasis in CRC patients after surgery was mSEPT9+ with stage III, mSEPT9- with stage III/mSEPT9+ with stage II, and mSEPT9- with stage II (P = 0.001), from highest to lowest. In addition, mSEPT9 was strongly associated with TNM staging, tumor immersion depth, distant metastasis, differentiation degree, vascular invasion and microsatellite. When we explored the associations between septin 9 protein level revealed by IHC and other elements, recurrence/progression (R = - 0.523, P = 0.001), mSEPT9 status (R = - 0.451, P = 0.004) and T stage (R = - 0.375, P = 0.017) showed significant correlations.

CONCLUSIONS

Positive mSEPT9 is a poor prognostic marker for CRC patients in stage II and III. It is also a powerful complement to TNM staging in predicting postoperative DFS of CRC patients of stage II and III.